Legionnaires’ disease a risk for gardeners, landscapers and farmers

Waikato DHB has seen a rise in notifications of legionella cases this year – currently 18 cases compared to just two for the same period in 2014.

Medical Officer of Health Dr Richard Wall says a nationwide study on legionella has led to increased testing for this disease, which will have contributed to this increase in notifications. “Investigation of these cases has found that the majority are linked to gardening and the use of potting mix and compost. Thirteen cases have required hospitalisation.”

One strain of the bacteria which causes Legionellosis (also known as Legionnaires’ disease) is a particular risk to home gardeners and farmers as it naturally occurs in soils, compost, and potting mix.

Bulk compost, soil and mulch doesn’t come with the same warnings as pre-packed products, so it is important to remember to take precautions.

“This is the time of year when we head out into the garden and so we are at increased risk of Legionella from working with or handling these products,” Wall says. “Packaging for products such as compost and potting mix includes a health warning and advice, but when you are buying in bulk there is no packaging and so some people may be unaware of the risks and precautions that should be taken.”

Legionnaires’ disease is a chest condition with symptoms similar to pneumonia. It can range in severity from a mild flu-like illness to a more severe respiratory condition. Common early symptoms include loss of appetite, muscle aches and pains, headache, abdominal pains and diarrhoea, with fever/chills, a dry cough and shortness of breath developing as the disease progresses. The disease is more common in middle-aged and older people, smokers, and people who have poor immunity or have a chronic illness. Young, fit and healthy people are less commonly affected.

The disease isn’t spread from person to person, but it can be a serious illness that requires hospital treatment.

Anyone who develops such symptoms within 2 – 10 days after handling soil, soil-type products, mulches, potting mix or compost should see their doctor.

To reduce the risk of exposure to Legionella bacterium the following steps can be taken:

Read the warning on bags of compost or potting mix

Wear a dust mask when opening bags or using compost or potting mix to avoid inhaling dust

Open bags of soil products, mulches compost or potting mix in a well ventilated area and away from the face

Dampen potting mix before use

Water your garden and indoor plants using a gentle spray

Wear gloves and wash hands thoroughly after working with soil products, mulches compost or potting mix

A booklet on safer and healthier gardening is available on the HealthEd website: